Gravitational Waveforms

The gravitational wavetrain from a compact binary system may be separated into three qualitatively different phases: the inspiral, merger, and ringdown. During the inspiral phase, which takes up most of the binary's lifetime, gravity wave emission gradually reduces the binary separation. When the black holes get close enough, they merge into one black hole. Finally, ringdown radiation is emitted as the distorted black hole settles down to Kerr-like equilibrium. Both polarization modes (h+ and hx) are shown.

Here, we track two black holes with equal mass inspiraling towards each other surrounded by a gaseous disk. Shown below are hx and h+ in just the lower hemisphere. Waveforms are plotted in the region of r/M ≥ 78. The evolution is followed through inspiral, merger, and ringdown. The matter is now evolved by solving the relativistic MHD equations and the gravitational field is evolved by solving the Einstein field equations via the BSSN formalism.